Intermittant Horde / Webmail Error

[chrome]

We have a customer who is receiving this error occasionally, and before i go changing permissions and following what the error tells us, I'd like to see if anyone else is getting this error, and if the chmod fixed this without breaking something else?

Error opening /var/lib/squirrelmail/prefs/default_pref
Could not create initial preference file!
/var/lib/squirrelmail/prefs/ should be writable by user apache Please contact your system administrator and report this error.

Thank you

Chrome